Brent Edward Hagel

A dynamic model of etiology in sport injury: the recursive nature of risk and causation.

The purpose of this manuscript is to outline a new model representing a dynamic approach that incorporates the consequences of repeated participation in sport, both with and without injury. This model builds on the previous work, while emphasizing the fact that adaptations occur within the context of sport (both in the presence and absence of injury) that alter risk and affect etiology in a dynamic, recursive fashion. Regardless of the type of injury, it is often preceded by a chain of shifting circumstances that, when they come together, constitute sufficient cause to result in an injury. If we are to truly understand the etiology of injury and target appropriate prevention strategies, we must look beyond the initial set of risk factors that are thought to precede an injury and take into consideration how those risk factors may have changed through preceding cycles of participation, whether associated with prior injury or not. This model considers the implications of repeated exposure, whether such exposure produces adaptation, maladaptation, injury or complete/incomplete recovery from injury. When feasible, future studies on sport injury prevention should adopt a methodology and analysis strategy that takes the cyclic nature of changing risk factors into account to create a dynamic, recursive picture of etiology.

Risk of Injury Associated With Body Checking Among Youth Ice Hockey Players

CONTEXT Ice hockey has one of the highest sport participation and injury rates in youth in Canada. Body checking is the predominant mechanism of injury in leagues in which it is permitted. OBJECTIVE To determine if risk of injury and concussion differ for Pee Wee (ages 11-12 years) ice hockey players in a league in which body checking is permitted (Alberta, Canada) vs a league in which body checking is not permitted (Quebec, Canada). DESIGN, SETTING, AND PARTICIPANTS Prospective cohort study conducted in Alberta and Quebec during the 2007-2008 Pee Wee ice hockey season. Participants (N = 2154) were players from teams in the top 60% of divisions of play. MAIN OUTCOME MEASURES Incidence rate ratios adjusted for cluster based on Poisson regression for game- and practice-related injury and concussion. RESULTS Seventy-four Pee Wee teams from Alberta (n = 1108 players) and 76 Pee Wee teams from Quebec (n = 1046 players) completed the study. In total, there were 241 injuries (78 concussions) reported in Alberta (85 077 exposure-hours) and 91 injuries (23 concussions) reported in Quebec (82 099 exposure-hours). For game-related injuries, the Alberta vs Quebec incidence rate ratio was 3.26 (95% confidence interval [CI], 2.31-4.60 [n = 209 and n = 70 for Alberta and Quebec, respectively]) for all injuries, 3.88 (95% CI, 1.91-7.89 [n = 73 and n = 20]) for concussion, 3.30 (95% CI, 1.77-6.17 [n = 51 and n = 16]) for severe injury (time loss, >7 days), and 3.61 (95% CI, 1.16-11.23 [n=14 and n=4]) for severe concussion (time loss, >10 days). The estimated absolute risk reduction (injuries per 1000 player-hours) that would be achieved if body checking were not permitted in Alberta was 2.84 (95% CI, 2.18-3.49) for all game-related injuries, 0.72 (95% CI, 0.40-1.04) for severe injuries, 1.08 (95% CI, 0.70-1.46) for concussion, and 0.20 (95% CI, 0.04-0.37) for severe concussion. There was no difference between provinces for practice-related injuries. CONCLUSION Among 11- to 12-year-old ice hockey players, playing in a league in which body checking is permitted compared with playing in a league in which body checking is not permitted was associated with a 3-fold increased risk of all game-related injuries and the categories of concussion, severe injury, and severe concussion.

Effectiveness of helmets in skiers and snowboarders: case-control and case crossover study

Abstract Objective To determine the effect of helmets on the risk of head and neck injuries in skiers and snowboarders. Design Matched case-control and case crossover study. Setting 19 ski areas in Quebec, Canada, November 2001 to April 2002. Participants 1082 skiers and snowboarders (cases) with head and neck injuries reported by the ski patrol and 3295 skiers and snowboarders (controls) with non-head or non-neck injuries matched to cases at each hill. Main outcome measures Estimates of matched odds ratios for the effect of helmet use on the risk of any head or neck injury and for people requiring evacuation by ambulance. Results The adjusted odds ratio for helmet use in participants with any head injury was 0.71 (95% confidence interval 0.55 to 0.92), indicating a 29% reduction in the risk of head injury. For participants who required evacuation by ambulance for head injuries, the adjusted odds ratio for helmet use was 0.44 (0.24 to 0.81). Similar results occurred with the case crossover design (odds ratio 0.43, 0.09 to 1.83). The adjusted odds ratio for helmet use for participants with any neck injury was 0.62 (0.33 to 1.19) and for participants who required evacuation by ambulance for neck injuries it was 1.29 (0.41 to 4.04). Conclusions Helmets protect skiers and snowboarders against head injuries. We cannot rule out the possibility of an increased risk of neck injury with helmet use, but the estimates on which this assumption is based are imprecise.

Rates and Risks of Injury during Intercollegiate Basketball

Background Previous studies of basketball injury have not been able to assess injury incidence and risk. Purpose To determine rates and risks of injury in Canadian intercollegiate basketball. Study Design Prospective cohort study. Methods Standardized data were collected with a validated instrument from 98.1% of the 318 athletes on the eight mens basketball teams in the Canada West Division of the Canadian Intercollegiate Athletic Union. Results A total of 142 athletes sustained 215 injuries (44.7% of players injured) over the 2-year study period. The greatest number of injuries resulting in more than seven sessions of time loss involved the knee, whereas the most common injuries causing fewer than seven sessions of time loss involved the ankle. The most common mechanism of injury was contact with another player, especially in the “key.” Injuries occurred 3.7 times more often in games than during practice. Centers had the highest rate of injury, followed by guards, and then forwards. The relative risk of reinjury was significantly increased by previous injuries to the elbow, shoulder, knee, hand, lower spine or pelvis, and by concussions. Conclusions Risk factors for injury were previous injury, games as opposed to practice, player position, player contact, and court location.

The effect of helmets on the risk of head and neck injuries among skiers and snowboarders: a meta-analysis.

Background: The prevention of head injuries in alpine activities has focused on helmets. However, no systematic review has examined the effect of helmets on head and neck injuries among skiers and snowboarders. Methods: We searched electronic databases, conference proceedings and reference lists using a combination of the key words “head injury or head trauma,” “helmet” and “skiing or snowboarding.” We included studies that used a control group; compared skiers or snowboarders with and without helmets; and measured at least one objectively quantified outcome (e.g., head injury, and neck or cervical injury). Results: We included 10 case–control, 1 case–control/case-crossover and 1 cohort study in our analysis. The pooled odds ratio (OR) indicated that skiers and snowboarders with a helmet were significantly less likely than those without a helmet to have a head injury (OR 0.65, 95% confidence interval [CI] 0.55–0.79). The result was similar for studies that used controls without an injury (OR 0.61, 95% CI 0.36–0.92), those that used controls with an injury other than a head or neck injury (OR 0.63, 95% CI 0.52–0.80) and studies that included children under the age of 13 years (OR 0.41, 95% CI 0.27–0.59). Helmets were not associated with an increased risk of neck injury (OR 0.89, 95% CI 0.72–1.09). Interpretation: Our findings show that helmets reduce the risk of head injury among skiers and snowboarders with no evidence of an increased risk of neck injury.

An international review of head and spinal cord injuries in alpine skiing and snowboarding

Background: Alpine skiing and snowboarding are popular winter activities worldwide, enjoyed by participants of all ages and skill levels. There is some evidence that the incidence of traumatic brain injury (TBI) and spinal cord injury (SCI) in these activities may be increasing. These injuries can cause death or severe debilitation, both physically and emotionally, and also result in enormous financial burden to society. Indeed, TBI is the leading cause of death and catastrophic injury in the skiing and snowboarding population. Furthermore, there are severe limitations to therapeutic interventions to restore neurological function after TBI and SCI, and thus the emphasis must be on prevention. Objectives: (1) To examine the worldwide epidemiology of TBI and SCI in skiing and snowboarding; (2) to describe and examine the effectiveness of prevention strategies to reduce the incidence of TBI and SCI in skiing and snowboarding. Search strategy: Searches were performed on a variety of databases to identify articles relevant to catastrophic central nervous system injury in skiing and snowboarding. The databases included PubMed, Medline, EMBASE, CDSR, ACP Journal Club, DARE, CCTR, SportDiscus, CINAHL, and Advanced Google searches. Selection criteria and data collection: After initial prescreening, articles included in the review required epidemiological data on SCI, TBI, or both. Articles had to be directly associated with the topic of skiing and/or snowboarding and published between January 1990 and December 2004. Results: 24 relevant articles, from 10 different countries, were identified. They indicate that the incidence of TBI and SCI in skiing and snowboarding is increasing. The increases coincide with the development and acceptance of acrobatic and high-speed activities on the mountains. There is evidence that helmets reduce the risk of head injury by 22–60%. Head injuries are the most common cause of death among skiers and snowboarders, and young male snowboarders are especially at risk of death from head injury. Conclusions: There should be enhanced promotion of injury prevention that includes the use of helmets and emphasizes the skier’s and snowboarder’s responsibility code.

Effectiveness of bicycle helmet legislation to increase helmet use: a systematic review.

Background: Head injuries related to bicycle use are common and can be serious. They can be prevented or reduced in severity with helmet use; however, education has resulted in modest helmet use in most developed countries. Helmet legislation has been proposed as a method to increase helmet wearing; while this social intervention is thought to be effective, no systematic review has been performed. Objectives: This review evaluates the scientific evidence for helmet use following legislation to identify the effectiveness of legislative interventions to increase bicycle helmet use among all age groups. Search strategy: Comprehensive searches of CENTRAL, MEDLINE, EMBASE, CINAHL, Web of Science, British Education Index, LILACS Database, TRIS (Transport Research Information Service), the grey literature, reference lists, and communication with authors was performed to identify eligible studies. Selection criteria: Eligible studies for this review were community based investigations including cohort studies, controlled before-after studies, interrupted time series studies, non-equivalent control group studies Data collection and analysis: Two reviewers extracted the data regarding the percentage of helmet use before and after legislation from each study. Individual and pooled odds ratios were calculated along with 95% confidence intervals. Main results: Out of 86 prescreened articles, 25 were potentially relevant to the topic and 11 were finally included in the review. Of 11 studies, eight were published articles, two were published reports, and one was an unpublished article. One additional survey was incorporated following personal communication with the author. While the baseline rate of helmet use among these studies varied between 4% and 59%, after legislation this range changed to 37% and 91%. Helmet wearing proportions increased less than 10% in one study, 10–30% in four studies, and more than 30% in seven studies. While the effectiveness of bicycle helmet legislation varied (n = 11 studies; OR range: 1.2–22), all studies demonstrated higher proportions of helmet use following legislation, particularly when the law was targeted to a specific age group. Conclusions: Legislation increased helmet use among cyclists, particularly younger age groups and those with low pre-intervention helmet wearing proportions. These results support legislative interventions in populations without helmet legislation.

The Effect of Wrist Guards on Wrist and Arm Injuries Among Snowboarders: A Systematic Review

Objective:To systematically review studies that examined the effectiveness of wrist guards in preventing wrist injuries among snowboarders. Data Source:MEDLINE (1966-March 2005), EMBASE (1988-March 2005), Cochrane (2005 Issue 1), Sport Discus (1975-March 2005) were searched using variations of the term “snowboard.” PubMED was searched for the year 2005 to capture any recently published studies not yet indexed in MEDLINE. The reference lists of included studies and conference proceedings were also searched. Study Selection:Studies were included if the number of wrist injuries between wrist guarded and unguarded snowboarders could be ascertained. Randomized controlled trials (RCTs), cohort studies, and case-control studies were included. Six studies were included. Data Extraction:Information regarding study design, patient characteristics, wrist guard characteristics, data source (for cohort and case-control studies), and results (type and severity of injury, compliance, and adverse events) were extracted. Data were extracted by one reviewer and checked by a second reviewer. Data Synthesis:Data from RCTs and cohort studies were expressed as relative risks with odds ratios presented for case-control studies. The risk of wrist injury (RR: 0.23; 95% CI: 0.13, 0.41), wrist fracture (RR: 0.29; 95% CI: 0.10, 0.87), and wrist sprain (RR: 0.17; 95% CI: 0.07, 0.41) was significantly reduced with the use of wrist guards. Among the case-control studies, wrist guards significantly lowered the odds of sustaining a wrist injury (OR: 0.46; 95% CI: 0.35, 0.62). In an RCT, the risk ratio suggested wrist guards protect the shoulder (RR: 0.22; 95% CI: 0.01, 4.60). Nonexperimental data suggested the possibility that wrist guards may increase the risk of finger and elbow-shoulder injuries. Conclusions:Wrist guards reduce the risk of wrist injuries among snowboarders. For every 50 snowboarders who were a wrist guard, one wrist injury will be averted. Future research should focus on determining the optimal type of wrist guard and if they increase the risk of other upper extremity injuries.

Risk of injury associated with bodychecking experience among youth hockey players

Background: In a previous prospective study, the risk of concussion and all injury was more than threefold higher among Pee Wee ice hockey players (ages 11–12 years) in a league that allows bodychecking than among those in a league that does not. We examined whether two years of bodychecking experience in Pee Wee influenced the risk of concussion and other injury among players in a Bantam league (ages 13–14) compared with Bantam players introduced to bodychecking for the first time at age 13. Methods: We conducted a prospective cohort study involving hockey players aged 13–14 years in the top 30% of divisions of play in their leagues. Sixty-eight teams from the province of Alberta (n = 995), whose players had two years of bodychecking experience in Pee Wee, and 62 teams from the province of Quebec (n = 976), whose players had no bodychecking experience in Pee Wee, participated. We estimated incidence rate ratios (IRRs) for injury and for concussion. Results: There were 272 injuries (51 concussions) among the Bantam hockey players who had bodychecking experience in Pee Wee and 244 injuries (49 concussions) among those without such experience. The adjusted IRRs for game-related injuries and concussion overall between players with bodychecking experience in Pee Wee and those without it were as follows: injury overall 0.85 (95% confidence interval [CI] 0.63 to 1.16); concussion overall 0.84 (95% CI 0.48 to 1.48); and injury resulting in more than seven days of time loss (i.e., time between injury and return to play) 0.67 (95% CI 0.46 to 0.99). The unadjusted IRR for concussion resulting in more than 10 days of time loss was 0.60 (95% CI 0.26 to 1.41). Interpretation: The risk of injury resulting in more than seven days of time loss from play was reduced by 33% among Bantam hockey players in a league where bodychecking was allowed two years earlier in Pee Wee compared with Bantam players introduced to bodychecking for the first time at age 13. In light of the increased risk of concussion and other injury among Pee Wee players in a league where bodychecking is permitted, policy regarding the age at which hockey players are introduced to bodychecking requires further consideration.

Risk factors for injury and severe injury in youth ice hockey: A systematic review of the literature

Objective To identify risk factors for injury in youth ice hockey (ie, body checking, age, player position, player experience and level of play). Study design Systematic review and meta-analysis. Methods A systematic review of the literature, including a meta-analysis component was completed. Ten electronic databases and the American Society for Testing and Materials Safety in Ice Hockey series (volumes 1–4) were systematically searched with strict inclusion and exclusion criteria to identify articles examining risk factors for injury in youth ice hockey. Results Participation in games, compared with practices, was associated with an increased risk of injury in all studies examined. Age, level of play and player position produced inconsistent findings. Body checking was identified as a significant risk factor for all injuries (summary rate ratio: 2.45; 95% CI 1.7 to 3.6) and concussion (summary odds ratio: 1.71; 95% CI 1.2 to 2.44). Conclusions Findings regarding most risk factors for injury remain inconclusive; however, body checking was found to be associated with an increased risk of injury. Policy implications regarding delaying body checking to older age groups and to only the most elite levels requires further rigorous investigation.